1. Field of Invention
This invention relates to a connector system for mechanically joining building panels (such as vinyl, laminate, or hardwood flooring); mechanically attaching decorative items (such as wall panels, ceiling panels, or automotive trim); mechanically attaching subsystems (such as automotive dashboards); or mechanically connecting elements of ready-to-assemble furniture.
2. Description of Related Art
FIG. 1 is a schematic drawing of the ubiquitous tongue and groove joining system typically used to join structural elements such as hardwood flooring. In the figure, hardwood flooring substrate element 1 with decorative surface 2 is to be connected to hardwood flooring substrate element 3 with decorative surface 4. A solid tongue 5 is machined from the solid substrate material with the resultant loss of saleable decorative surface 6. A mating groove 7 is formed in substrate element 3 to accept tongue 5. The structural elements are joined by moving element 3 in the direction of the arrow so as to cause mating groove 7 to receive tongue 5. The tongue is normally forcibly received into its mating groove and once received, the tongue, though held in place by friction, is not actively drawn into the groove
Additional prior art is found in U.S. patent application Ser. No. 12/705,593, EFS ID 7006498 of Baker and Vitale which discloses a method for “Laying and Mechanically Joining Building Panels or Construction Elements”. The mating groove described in this patent application is shown in FIG. 2. The Baker/Vitale patent application describes a system that is similar to that of the present patent application but differs in the following two significant ways:                1. The locking steps located at the distal end of the Baker/Vitale mating groove can only be fabricated using a device such as a rotary router cutter or a linear broach cutter, neither of which are consistent with high speed commercial flooring production.        2. The connector and mating groove interaction in the Baker/Vitale system is more sensitive to geometric deviations arising from manufacturing tolerances.        
The differences noted above are a consequence of the mating groove geometry associated with the Baker/Vitale patent application. As seen in FIG. 2, the mating groove 27 has steps 8 and 9 near its distal end. These steps are intended to interact with catches on a mating split-tongue connector in such a manner as to forcibly draw the connector into the groove.
As shown in FIG. 2, a hold region extension line 10 drawn parallel to step 8 does not exit the groove through the groove entrance region 11 but rather intersects the opposite sidewall of the groove at 12. Consequently, steps 8 and 9 must be formed using either a rotary router cutting tool 13 as shown in FIG. 3A, or a linear broach cutting tool 14, as shown in FIG. 3B. As seen in FIG. 3A, the diameter 16 of the router cutting tool is limited to the maximum distance 15 between the outer surfaces of the steps. That is, in contradistinction to the connector system disclosed in this application, the diameter of the rotary cutting tool cannot be made larger than the maximum groove width.
Due to the limited rotary cutter diameter shown in FIG. 3A, the rotary approach is precluded, by tool heating and chip removal considerations, from forming a mating groove at the speeds (i.e., approximately 360 linear feet per minute) consistent with economical production of the thousands of linear feet of groove typically required in commercial vinyl, laminate, or hardwood flooring. The broach approach to groove fabrication shown in FIG. 3B, faces similar heating and chip removal obstacles relative to the same commercial application.
It should be noted, however, that although the rotary router approach is precluded, by economics, from use in high-speed flooring production; it can be used in other commercial applications, such as ready-to-assemble (RTA) furniture, where groove linear dimensions are only 2″ to 3″ and low-speed groove fabrication is economically viable.